PLANT ASSOCIATIONS 229 
“Ecology of Woodland Plants,” by T. W. Woodhead,* 
and ‘‘ Marsh Vegetation,” by Professor Yapp,t should be 
consulted. 
In a large district, where many associations exist, the 
limits of each type should be recorded on a map, and 
distinguished by some definite system of colouring, as 
in the vegetation survey-maps of Smith, Moss, Lewis 
and Pethyridge. 
The following summary of the associations and groups 
of associations to be dealt with is taken, with slight 
modification, from W. G. Smith’s Botanical Survey of 
Scotland : III. and IV. Forfar and Fife :-— 
A. Associations with a Water-Supply comparatively 
rich in Plant-Food. 
I. Forest. 
1. Moist soils : 
(a) Oakwood - Associations. — On  non- 
peaty soils at low and moderate 
elevations (p. 269). 
(6) Oak-Bireh-Heath Association. — On 
dry, coarse, sandy, and dry!peaty 
soils at low elevations (p. 271). 
(c) Birchwood - Association. —On non- 
calcareous soils at high elevations 
p.- 24); 
(qd) Ash-Oakwood Association.—On cal- 
careous clays, marls, impure lime- 
stones, and calcareous sandstones 
(p. 272). 
(e) AShwood-Association.—On limestones 
@ (p. 272). 
(f ) Beechwood - Association.—On chalk 
in the south-east of England and 
on oolite in the Cotswold Hills 
(p 272). 
2. Wet soils : 
Alder and Willow-Thickets (p. 243). 
* Journal of the Linnean Society : Botany, vol. xxxvii., p. 333. 
t Annals of Botany, vol. xxiii., p. 275; New Phytologist, vol. vii., 
p. 61. 
